As a normal user, I'd edited some files that ordinarily ordinary users wouldn't be editing (specifically, Intellij IDEA
.vmoptions files, in
C:\Program Files (x86)\JetBrains\Intellij IDEA 10.5.2\bin), without the effects I was hoping for, and I saw some noise elsewhere on the web about administrators and normal users seeing different versions of these files (???!), so I decided to try to edit them as administrator.
I launched Windows Explorer using "Run as administrator" and navigated to the folder. As far as Windows Explorer was concerned, the files didn't exist. (Note: "Show hidden files and folders" was AFAICT enabled for both me as ordinary user and for administrator.) I tried using Notepad (again as administrator; administrator-Notepad's File|Open dialog couldn't see the files either) to create a new file and save it over one of the files I couldn't see, and this appeared to succeed but did not change the file. (It did, however, change the modification date of the directory.)
Finally, as myself, I moved the files to the desktop, and then dragged them into the admin Explorer window, at which point they became visible and I was able to change the ownership from myself to administrator. They seem to have stayed visible since.
But what the @$#! is going on? I assume Windows 7 is doing something terribly clever and helpful, but I have no idea what it is.
(FWIW, my original edits were done with XEmacs under cygwin, and the problem, as best I can make out, was a straightforward one of the wrong type of line ending. But with Explorer behaving this way, I can't be sure.)